Graph-based timing analysis timing calibration

Abstract

A set of multi-corner multimode (MCMM) databases that correspond to a set of working scenarios are accessed. A full timing update on the set of MCMM databases, for the set of working scenarios, is applied. A graph based analysis (GBA) timing calibration is performed on the databases, for the set of working scenarios to obtain a set of GBA-calibrated databases. Multiphase optimizations on the set of GBA-calibrated databases are iteratively performed to generate a set of optimized databases, including: performing a phase-specific optimization on the set of GBA-calibrated database to obtain an improved set of databases, and recalibrating GBA timing on the set of improved databases prior to a next phase-specific optimization.

What is claimed is: 
     
       1. A system, comprising:
 a processor configured to:
 access a set of multi-corner multimode (MCMM) databases that correspond to a set of working scenarios; 
 apply a full timing update on the set of MCMM databases, for the set of working scenarios; 
 perform a graph based analysis (GBA) timing calibration on the databases, for the set of working scenarios to obtain a set of GBA-calibrated databases; and 
 iteratively perform multiphase optimizations on the set of GBA-calibrated databases to generate a set of optimized databases, including:
 performing a phase-specific optimization on the set of GBA-calibrated databases to obtain an improved set of databases; and 
 recalibrating GBA timing on the set of improved databases prior to a next is phase-specific optimization; and 
 
 
 a memory coupled to the processor and configured to provide the processor with instructions. 
 
     
     
       2. The system of  claim 1 , wherein a MCMM database of the set of MCMM databases comprises a graph representation of a circuit design. 
     
     
       3. The system of  claim 1 , wherein a MCMM database of the set of MCMM databases comprises a graph representation of a circuit design and timing arc information in the graph representation. 
     
     
       4. The system of  claim 1 , wherein each MCMM database of the set of MCMM databases comprise a netlist. 
     
     
       5. The system of  claim 1 , wherein the full timing update includes path based analysis (PBA) and GBA. 
     
     
       6. The system of  claim 1 , wherein the processor is further configured to apply calibration to each of the set of MCMM databases for each of the set of working scenarios. 
     
     
       7. The system of  claim 1 , wherein the processor is further configured to release a PBA database for a plurality of working scenarios in the set of working scenarios. 
     
     
       8. The system of  claim 1 , wherein the phase-specific optimization includes a PBA and a GBA. 
     
     
       9. The system of  claim 1 , wherein the processor is further configured to release a PBA database after the step of recalibrating GBA timing. 
     
     
       10. The system of  claim 1 , wherein recalibrating GBA timing comprises:
 for an input pin in a PBA database, in the event a PBA path exists on the input pin:
 determining a most critical PBA path on the input pin; and 
 calculating an arrival time offset on the input pin; and 
 
 updating GBA timing with the calculated arrival time offset. 
 
     
     
       11. The system of  claim 10 , wherein calculating the arrival time offset is based at least in part on a difference between PBA and GBA arrival times. 
     
     
       12. The system of  claim 10 , wherein calculating the arrival time offset is based at least in part on a difference between a difference of PBA and GBA arrival times. 
     
     
       13. A method, comprising:
 accessing a set of multi-corner multimode (MCMM) databases that correspond to a set of working scenarios; 
 applying a full timing update on the set of MCMM databases, for the set of working scenarios; 
 performing a graph based analysis (GBA) timing calibration on the databases, for the set of working scenarios to obtain a set of GBA-calibrated databases; and 
 iteratively performing multiphase optimizations on the set of GBA-calibrated databases to generate a set of optimized databases, including:
 performing a phase-specific optimization on the set of GBA-calibrated databases to obtain an improved set of databases; and 
 recalibrating GBA timing on the set of improved databases prior to a next phase-specific optimization. 
 
 
     
     
       14. The method of  claim 13 , wherein the full timing update includes path based analysis (PBA) and GBA. 
     
     
       15. The method of  claim 13 , further comprising applying calibration to each of the set of MCMM databases for each of the set of working scenarios. 
     
     
       16. The method of  claim 13 , further comprising releasing a PBA database after the step of recalibrating GBA timing. 
     
     
       17. The method of  claim 13 , wherein recalibrating GBA timing comprises:
 for an input pin in a PBA database, in the event a PBA path exists on the input pin:
 determining a most critical PBA path on the input pin; and 
 calculating an arrival time offset on the input pin; and 
 
 updating GBA timing with the calculated arrival time offset. 
 
     
     
       18. The method of  claim 17 , wherein calculating the arrival time offset is based at least in part on a difference between PBA and GBA arrival times. 
     
     
       19. The method of  claim 17 , wherein calculating the arrival time offset is based at least in part on a difference between a difference of PBA and GBA arrival times. 
     
     
       20. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:
 accessing a set of multi-corner multimode (MCMM) databases that correspond to a set of working scenarios; 
 applying a full timing update on the set of MCMM databases, for the set of working scenarios; 
 performing a graph based analysis (GBA) timing calibration on the databases, for the set of working scenarios to obtain a set of GBA-calibrated databases; and 
 iteratively performing multiphase optimizations on the set of GBA-calibrated databases to generate a set of optimized databases, including:
 performing a phase-specific optimization on the set of GBA-calibrated databases to obtain an improved set of databases; and 
 recalibrating GBA timing on the set of improved databases prior to a next phase-specific optimization.